1. Field of the Invention
The present invention relates to the field of information handling systems, and more particularly to a method and system for determining external power available and fault states.
2. Description of the Related Art
As the value and use of information continues to increase, individuals and businesses seek additional ways to process and store information. One option available to users is information handling systems. An information handling system generally processes, compiles, stores, and/or communicates information or data for business, personal, or other purposes thereby allowing users to take advantage of the value of the information. Because technology and information handling needs and requirements vary between different users or applications, information handling systems may also vary regarding what information is handled, how the information is handled, how much information is processed, stored, or communicated, and how quickly and efficiently the information may be processed, stored, or communicated. The variations in information handling systems allow for information handling systems to be general or configured for a specific user or specific use such as financial transaction processing, airline reservations, enterprise data storage, or global communications. In addition, information handling systems may include a variety of hardware and software components that may be configured to process, store, and communicate information and may include one or more computer systems, data storage systems, and networking systems.
Information handling systems configured as portable computers have grown increasingly favored by businesses and individuals due to the increased flexibility of their use. Portable computers typically include a battery to power components so that the portable computer may be carried and used independent of fixed power sources. Although internal power sources provide greater flexibility, they typically have a limited duration and need periodic recharging. If portable computers are not recharged before the battery discharges completely, the portable computer may shutdown resulting in a loss of active data and an inability by the user to turn the portable computer system on again unless an external power source is connected. Thus, when a user grows low on battery charge, the user is typically provided notice of the low battery charge and urged to connect to an external power source.
One difficulty with portable computers is that a failed external power source may make a portable computer with a discharged battery unusable. If a user connects a failed external power source expecting to recharge the battery, the failure of the portable computer once the battery discharges will come as an unpleasant surprise. To provide notice of external power source operability, AC adapters sometimes include an LED light to indicate operation. However, these indicators do not confirm that current passes from the adapter through the adapter cable to the portable computer power adapter connection. For instance, a broken cable between the adapter and the adapter connection will fail to recharge the portable computer even if the adapter LED indicates good operations. Further, the portable computer has no indication of a power adapter connection in situations when no power is provided by the adapter and portable computer charger interfaced with the adapter.
Therefore a need has arisen for a method and system which determines a faulty external power state for an information handling system, such as with a broken external power cable.
A further need exists for a method and system which determines an external power state for a connection of the external power to the information handling system whether or not the connection provides power to the information handling system.
In accordance with the present invention, a system and method are provided which substantially reduces the problems and disadvantages associated with providing external power to an information handling system. An external power source identification signal provided from the external power source and an external power available signal are compared to determine an external power source state. An external power source fault is determined if the external power source identification and the external power source available signals are inconsistent.
More specifically, an information handling system configured as a portable computer has an external power source connector that connects to the DC power cable of an AC adapter and also connects to an identification signal wire from the AC adapter. The DC signal passes to an internal charger or other power supply which provides power to run the portable computer and recharge the battery of the portable computer. The charger provides an external power available signal to a subsystem manager, such as a Super I/O processor, when it receives power for use by the portable computer. The identification signal passes to the subsystem manager to allow identification of the type of external power source.
An external power state machine operates on the subsystem manager to determine the state of the external power source. If inconsistent power available and identification signals are sensed, the external power state machine determines an external power fault state. For instance, if the power available signal indicates no external power and the identification signal indicates an external power source, an external power fault state is determined. If the power available signal indicates an external power source and the identification signal indicates no external power source, an external power source fault state is determined. If both the identification and the power available signals indicate an external power source, an external power available state is determined, such as that an adapter is connected to the portable computer. If both the identification and the power available signals indicate that no external power source is connected, the an external power disconnected state is determined, such as that an adapted is not connected to the portable computer. The external power state is provided to the user, such as with LED indicators, an audible indicator or a display window.
The present invention provides a number of important technical advantages. One example of an important technical advantage is that an external power fault state is automatically determined and provided to the user of an information handling system. For instance, an external power system fault associated with a broken cable between the power adapter and the information handling system connector is detected with notice provided to the user. Trouble shooting external power source faults is simplified and more accurate.
Another example of an important technical advantage is that external power source states are determined and provided to information handling system users. For instance, detection of an AC adapter to a portable computer is made so that a portable computer user may be notified of the connection. Determination of specific external power source states allows notification to users of specific states through a display of a portable computer, such as with an operating system message.